Abstract
It is known that people divide spatial regions into categories to enhance perception and interaction with the environment. Boundaries or landmarks are known to affect spatial memory and target localization due to the development of biases related to these 'categories'. Spatial recall tasks widely used to assess developmental changes in spatial memory in adult and children have shown biases in localization towards or away from a visible boundary. Although spatial working memory impairments are is among the hallmark neurocognitive deficits observed in schizophrenia, the exact spatial recall processes and landmark effects that contribute to spatial perception in schizophrenia remain unknown. Here we studied the effect of a visual landmark on spatial recall performance in people with schizophrenia and healthy controls to investigate bias patterns within each group. The task began with a fixation period, after which a target was briefly presented at a randomized horizontal distance either to the left or right of a centrally placed vertical line segment that served as a visual landmark. The target was then extinguished and after a delay period of 2s, subjects were instructed to click on the screen to indicate its remembered location. Target localization errors (derived as angular distance between target location and mouse click position) were analyzed and compared between groups across distances from the landmark. We show that controls were biased towards the visual landmark, particularly for targets located further away, whereas for those with schizophrenia, responses were biased away from the visual landmark.. The pattern of biases could reflect atypical spatial recall mechanisms in schizophrenia, whereby representations of the category information (In this case, left or right of landmark) and precise target location (proximity to the landmark) are differentially weighted compared to controls.
Meeting abstract presented at VSS 2017